Abstract
All parts of Thanakha (Hesperethusa crenulata R.) have been used as traditional skin care herbal material in Myanmar. In this study, coumarins from H. crenulata R. bark were isolated through solvent extraction, systematic solvent fractionation, and repeated column chromatography. Spectroscopic analyses using ESI–MS, 1D NMR (1H and 13C), 2D NMR (gHSQC and gHMBC), specific rotation, circular dichroism, and IR spectrometry revealed three coumarins 2R-7-hydroxy-8-(2,3-dihydroxy-3-methylbutyl)-coumarin (compound 1), peucedanol (compound 2), and methylpeucedanol (compound 3), which were first isolated from Thanakha tree. Antioxidant capacities of three coumarins decreased as follows: compound 2 > compound 3 > compound 1. Treatments of lipopolysaccharide-induced THP-1 human monocytic cells with compounds 2 and 3 at 378.8 μM and 359.7 μM inhibited tumor necrosis factor-α production by approximately 32.7% and 13.3%, respectively, compared with the negative control. In summary, these results suggest that Thanakha bark extracts can be used as a potent antioxidant and anti-inflammatory source for cosmetic ingredients.
